With the increasing depletion of fossil fuels and increasing pressure on environmental pollution, automotive industry urgently needs a new type energy resource to provide driving force for automobiles, and lithium-ion battery is talent showing itself due to its high energy density, no memory effect and high operating voltage, which makes the lithium-ion battery become a first choice for a power supply of the new energy vehicles at present. However, with the expansion of the market demand for electronic products and development of power device and energy storage device, people's demand for the lithium-ion battery is continuously increasing, developing high energy density and fast charge-discharge lithium-ion battery becomes an urgent matter. At present, an effective method is to increase voltage and press density of an electrode active material and select appropriate electrolyte.
At present, an electrolyte widely used in the lithium-ion battery comprises lithium hexafluorophosphate (LiPF6) as an electrolyte salt and a mixture of cyclic carbonate ester and chain carbonate ester as an organic solvent, however the above electrolyte has many disadvantages, particularly under high voltage, high temperature storage performance of the lithium-ion battery is poor. The electrolyte, as an important part of the lithium-ion battery, has a significant influence on electrochemical performance of the lithium-ion battery. Therefore, how to further optimize the composition of the electrolyte is very important to improve performance of the lithium-ion battery.